Study On Steady Water Quality Modeling Of The Three Gorges Area In Chongqing Region

The Three Gorges Project on the Yangtze River is the world-famous largest hydroelectric project. It will possess comprehensive utilization benefits for flood control, power generation and navigation improvement. But the construction of TGP will produce widespread and profound impact on ecology and environment. Therefore, the water environmental issue after the dam being put into practice has become one of the focuses not only domestically but also overseas.The one-dimensional water quality model which based on the one-dimensional advection-dispersion mass transport equation was developed. Then, it was applied to calculate the water quality characteristics of the Three Gorges reservoir in Chongqing region: that was the 500km-long mainstream beginning at Cuntan and ending at the boundary of Chongqing. The parameters of the model were proved to be validating by used the gauged values in the normal,dry and wet seasons. The validating result indicated that the model properly reflected the holistic water quality characteristics, showing its ability of prediction. Further, the model was applied to predict the water quality characteristics of the calculating zone at the time of completion of the project (175m water lever at the dam).Meanwhile ,the paper established a two-dimensional random water quality model whose method of solution is MonteCarlo method. The empirical constant of the transverse diffusion coefficient was rating by used the gauged values of the pollution zone in the normal season in Huangshaxi of the Yangtze River. Then the empirical constant was verified by used the gauged values in the dry season. The validating result indicated that the model properly reflected the change of the pollution zone in the normal reason and the dry season , showing its ability of prediction. Further, the model was applied to predict the pollution zone in Huangshaxi of the Yangtze River at the time of completion of the project (175m water lever at the dam).The research results showed that:Although the cross-section average velocity reduced, the water depth increased and the degradation rate coefficients of COD_Mn and NH₃-N reduced at the time of completion of the project (175m water lever at the dam), the detention time sharply increased and total quantity of the self-purification increased. At the same time the pollution load of Chongqing city was reduced . the cross-section average COD_Mn and...